Cache-Aided Coded Multicast for Correlated Sources

The combination of edge caching and coded multicasting is a promising approach to improve the efficiency of content delivery over cache-aided networks. The global caching gain resulting from content overlap distributed across the network in current solutions is limited due to the increasingly personalized nature of the content consumed by users. In this paper, the cache-aided coded multicast problem is generalized to account for the correlation among the network content by formulating a source compression problem with distributed side information. A correlation-aware achievable scheme is proposed and an upper bound on its performance is derived. It is shown that considerable load reductions can be achieved, compared to state of the art correlation-unaware schemes, when caching and delivery phases specifically account for the correlation among the content files.Comment: In proceeding of IEEE International Symposium on Turbo Codes and Iterative Information Processing (ISTC), 201

Correlation-Aware Distributed Caching and Coded Delivery

Cache-aided coded multicast leverages side information at wireless edge caches to efficiently serve multiple groupcast demands via common multicast transmissions, leading to load reductions that are proportional to the aggregate cache size. However, the increasingly unpredictable and personalized nature of the content that users consume challenges the efficiency of existing caching-based solutions in which only exact content reuse is explored. This paper generalizes the cache-aided coded multicast problem to a source compression with distributed side information problem that specifically accounts for the correlation among the content files. It is shown how joint file compression during the caching and delivery phases can provide load reductions that go beyond those achieved with existing schemes. This is accomplished through a lower bound on the fundamental rate-memory trade-off as well as a correlation-aware achievable scheme, shown to significantly outperform state-of-the-art correlation-unaware solutions, while approaching the limiting rate-memory trade-off.Comment: In proceeding of IEEE Information Theory Workshop (ITW), 201

Sectoring in Multi-cell Massive MIMO Systems

In this paper, the downlink of a typical massive MIMO system is studied when each base station is composed of three antenna arrays with directional antenna elements serving 120 degrees of the two-dimensional space. A lower bound for the achievable rate is provided. Furthermore, a power optimization problem is formulated and as a result, centralized and decentralized power allocation schemes are proposed. The simulation results reveal that using directional antennas at base stations along with sectoring can lead to a notable increase in the achievable rates by increasing the received signal power and decreasing 'pilot contamination' interference in multicell massive MIMO systems. Moreover, it is shown that using optimized power allocation can increase 0.95-likely rate in the system significantly

Broadcast Caching Networks with Two Receivers and Multiple Correlated Sources

The correlation among the content distributed across a cache-aided broadcast network can be exploited to reduce the delivery load on the shared wireless link. This paper considers a two-user three-file network with correlated content, and studies its fundamental limits for the worst-case demand. A class of achievable schemes based on a two-step source coding approach is proposed. Library files are first compressed using Gray-Wyner source coding, and then cached and delivered using a combination of correlation-unaware cache-aided coded multicast schemes. The second step is interesting in its own right and considers a multiple-request caching problem, whose solution requires coding in the placement phase. A lower bound on the optimal peak rate-memory trade-off is derived, which is used to evaluate the performance of the proposed scheme. It is shown that for symmetric sources the two-step strategy achieves the lower bound for large cache capacities, and it is within half of the joint entropy of two of the sources conditioned on the third source for all other cache sizes.Comment: in Proceedings of Asilomar Conference on Signals, Systems and Computers, Pacific Grove, California, November 201

A comparative survey on the effects of rhinoplasty on confidence and happiness

Introduction: With regard to the increasing aesthetic solutions through makeup and plastic surgeries, high rate of cosmetics sales in Iran, and increased office visit for plastic surgeries, the purpose of this study is to analysis the effect of rhinoplasty on self-confidence and happiness of women aged 16 to 35 who were visited in private clinics in Urmia city in December 2014.Materials and Methods: The study performed on 40 women who have undertaken rhinoplasty, 40 women who were waiting for rhinoplasty, and a group of 40 women who have not undergone rhinoplasty. Copper Smith self-esteem questionnaire including 58 questions and Oxford Happiness Questionnaire including 29 questions have been used in this study.Results: The results of student’s t-test for independent groups showed that from the aspects of self-esteem and happiness, there was a difference between the group who have done surgery and those who were standing by.Discussion and Conclusion: The findings show that self-esteem and happiness of the people who undergone rhinoplasty is equal and even more than those who were standing by for this operation or have not taken the operation.

On Coding for Cache-Aided Delivery of Dynamic Correlated Content

Cache-aided coded multicast leverages side information at wireless edge caches to efficiently serve multiple unicast demands via common multicast transmissions, leading to load reductions that are proportional to the aggregate cache size. However, the increasingly dynamic, unpredictable, and personalized nature of the content that users consume challenges the efficiency of existing caching-based solutions in which only exact content reuse is explored. This paper generalizes the cache-aided coded multicast problem to specifically account for the correlation among content files, such as, for example, the one between updated versions of dynamic data. It is shown that (i) caching content pieces based on their correlation with the rest of the library, and (ii) jointly compressing requested files using cached information as references during delivery, can provide load reductions that go beyond those achieved with existing schemes. This is accomplished via the design of a class of correlation-aware achievable schemes, shown to significantly outperform state-of-the-art correlation-unaware solutions. Our results show that as we move towards real-time and/or personalized media dominated services, where exact cache hits are almost non-existent but updates can exhibit high levels of correlation, network cached information can still be useful as references for network compression.Comment: To apear in IEEE Journal on Selected Areas in Communication

The Comparison of Community –based Education Programs in Faculties of Tabriz University of Medical Sciences

Introduction: Training in a real work environment, within community is an effective method of education. Continuous evaluation of community based education courses is essential for both maintaining and improving their quality. Methods: In a cross-sectional study, 100 students who had passed community based education courses along with 15 faculty members teaching the same courses have been randomly selected in the faculties of Tabriz University of medical sciences. A researcher-designed questionnaire consisting questions of educational program, learning settings, teaching and assessment methods, used for data collection. The data was analyzed using SPSS16. Results: Community based education among the students of Health and Nutrition, Dentistry, Para medicine, Pharmacy, Medicine, Nursing and Rehabilitation faculties scored 39.466.59± (average), 78.201.37± (very high), 52.7814.41± (high), 19.485.29± (low), 61.942.22.2± (good), 43.9716.82± (average) and 64.903.45± (high), respectively. Conclusion: The research results showed that community based education had different quality levels in different departments